The changes will not require new legislation and are aimed at tackling "individuals who foster extremism or hate" - including radical Islamists, neo-Nazis and violent animal rights activists.

Shadow Home Secretary Dominic Grieve was dismissive of the changes, saying: "This announcement is more spin than substance. The real issue is preventing extremists from coming here, not advertising it after the event.

"If the home secretary is at last committed to applying the powers she has, robustly and consistently, then we welcome it, but why has it taken this government so long?"

The measures announced will:

create a presumption in favour of exclusion for people who have engaged in fostering, encouraging or spreading extremism and hatred

put the burden of proof on individuals to show they have renounced previous extremist views

allow for the exclusion of nationals from the European Economic Area before they travel to the UK

increase co-operation with other agencies to improve the evidence base underpinning exclusions

allow for the "naming and shaming" of excluded people

The measures do not go far enough, according to Liberal Democrat home affairs spokesman Chris Huhne, who also said naming extremists was a "tawdry gimmick" that could lead to ministers being sued for libel.

He said: "It is quite right to exclude anyone whose speech is likely to prove so inflammatory as to provoke violence or racial hatred, but these ideas add nothing since the government has already excluded 79 preachers of hate in three years.

"The real need is for quiet intelligence to tackle British preachers of hate, and to block hate-filled internet sites.

"Given the Home Office's track record of error, there must be adequate safeguards and checks to stop the exclusion of innocent people."

Keith Vaz, chairman of the Home Affairs Committee, said there should be tougher measures to help remove foreigners inciting violence who are already based in the UK.

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Patrick Mercer MP and Inayat Bunglawala say the proposals are a "gimmick"

He said: "Along with being tougher on those wanting to enter the UK we must also get tougher on removing those that are already here.

"If they are convicted of inciting violence or related offences, they must be removed."

Mr Vaz also said he was concerned information used to make exclusion decisions needed to be accurate, and that there needed to be a clear process in which to challenge a decision.

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